There is known an LED (electric) bulb in which an LED (light emitting diode) module serving as a lighting source is covered with a glove so as to provide an outer appearance of a filament bulb. For the LED, as a temperature thereof rises, an optical output becomes reduced and a life time is also shortened, so that it is required, for a lamp using an LED as the light source, to suppress the temperature of the LED from rising.
Thus, there has been provided a known LED bulb in which heat dissipation characteristics of the LED could be improved without increasing the manufacturing cost (for example, refer to Patent Document 1). According to Patent Document 1, a printed circuit board having an LED mounted thereon is contained in a metal body having a plurality of heat dissipating fins so that the LED is mounted on the printed circuit board to be close to an internal surface of the body, thereby allowing the heat dissipating fins of the body to dissipate the heat of the LED.
Further, a power source circuit (lighting circuit) generating an electric power for the LED is mounted and formed in another printed circuit board arranged separately from the above-mentioned printed circuit board to be disposed in an inner hollow portion of the body.
Patent Document 1: Japanese Patent Laid-Open No. 2006-40727